Conventional air cooling systems for electronics racks can be categorized into one of two types—stacked single-shelf systems and full-rack systems. The stacked single-shelf systems are typically in either a bottom-to-top, front-to-back, or side-to-side air flow configuration. The shelves are stacked in the electronics rack, with each individual shelf, as well as their combined effect, creating an air cooling system for the electronics rack. The full-rack systems are typically in a bottom-to-top, or chimney, air flow configuration. Both types of conventional air cooling systems suffer from significant limitations.
The bottom-to-top air flow configuration stacked single-shelf systems require vertical space in the electronics rack below and above each shelf for air intake and exhaust plenums. This limits the space available for electronics. The front-to-back air flow configuration stacked single-shelf systems utilize an air intake area that limits the electronics module faceplate room available for front connectivity and an air exhaust area that limits the backplane available for back connectivity. The side-to-side air flow configuration stacked single-shelf systems utilize air intake and exhaust areas that are often blocked by the electronics rack structure and air intake and exhaust volumes that detract from the available volume in the shelf for electronics. The bottom-to-top, or chimney, air flow configuration full-rack systems suffer from the limitation that the preheating of the air stream entering the upper shelves in the electronics rack due to heat dissipation in the lower shelves of the electronics rack limits the amount of power that can be utilized in the upper-shelf electronics.
Thus, what is still needed in the art is an air cooling system for an electronics rack that overcomes these limitations.